Random Quiz Questions Flashcards
The difference between sphingomylein (SM) and phosphatidylcholine (PC) is that:
SM backbone is derived from serine while PC backbone is glycerol
Which of the following is a source of heterogeneity in the plasma membrane?
-Differences in the polar head groups of the lipids
-Differences in the fatty acids (nonpolar tail groups)
-Differences in the amphipathic nature of the membrane
-Two of the above
-All of the above
Two of the above
Which of the following receptors involves tetramer formation during activation?
Receptor Tyrosine Kinases
Activation of a receptor guanylyl cyclase can take place ____ and causes ____
on the cell surface or in the cytosol; an increase in the cGMP level
Which of the following is a mechanism for activation of receptor tyrosine kinases?
-Dimerization of the receptors by a ligand dimer
-Relief of autoinhibition by ligand binding
-Change in conformation of a preformed receptor dimer induced by ligand binding
-Two of the above
-All of the above
All of the above
SC binds KIT on the surface of the cell. This induces KIT dimerization and the activation of a kinase on the cytoplasmic side of the membrane. The kinase phosphorylates a number of cellular proteins that activate a pathway. In this example, KIT is a ____
Receptor
In which receptor family is ceramide a product of receptor activation?
Sphingomyelinase-linked receptor
Adaptation by seven-helix receptors involves which of the following?
Phosphorylation of the C-terminal tail
Which kinetochore protein(s) bridge the inner and outer kinetochore group of microtubule binding proteins?
CENP-C
Euchromatin is ____ densely packed than heterochromatin, is ___ accessible for transcription, and is like to be found more in the ___ of the nucleus
Less; more; center
Removal of an acetyl group from ____ on histone tails causes the associated DNA to be ____ accessible for transcription
Lysine; less
Ran has just entered the nucleus through a nuclear pore. Put the events below in chronological order from this event onward
1. Ran binds importin-beta
2. Ran hydrolyzes GTP
3. Ran leaves the nucleus through the nuclear pore
1,3,2
What is found in the central passageway (lumen) through the nuclear pore complex?
The FG repeats of nucleoporins
The GEF for Ran is located in the ___. The GAP for Ran is located in the ___
Nucleus; cytoplasm
Nitric oxide (NO) is a second messenger that is synthesized when needed. Which of the following amino acids is the starting material for NO synthesis?
Arginine
Which portion of the nucleus is most closely associated with the endoplasmic reticulum?
Outer nuclear membrane
Which of the following is true regarding HP1?
-It binds to specific forms of modified histones
-It interacts with the lamin B receptor
-It can recruit the enzyme Suv39
-Two of the above
-All of the above
All of the above
In which nuclear subdomain would you expect to find factors involved in DNA repair?
53BP1 nuclear bodies
What is the role of the CaaX box found at the C-terminus of lamins?
It facilitates membrane anchoring of lamins
In which phase of the ATPase cycle does myosin have a low affinity for actin filaments?
Myosin bound to ATP
Disassembly of the lamin network is caused by which of the following
Activation of lamin depolymerase
Which of the following is the force generating step in the myosin ATPase cycle?
Release of gamma phosphate
Microtubule dynamics (polymerization and depolymerization) are highest at the plus end of the microtubule. This is the end that has __- tubulin exposed. At this end, _
-bound tubulin is more likely
to polymerize than it is to depolymerize.
Beta; GTP
When AAA1 of dynein ___ the hexamer becomes more compact, causing the buttress to shift along the stalk, causing the dynein to bind ___ to the microtubule.
Binds ATP; weakly
